My 72 heads looks like that .
The head I have, the bolt head actually sits were the yellow line above boss ends, right down where the top fin is.. not up on top of the rib..the rib is split in to rwo parts, the bolt head is DOWN in between them and flush to the fin.
Mine looks similar to the pic inHEAD MARKING thread. on my 72's the bolt head is higher, the height if the rib with a boss in the area to support the bolt, ie bolt sits about 8 or 10 mm higher up.